Shigetaka Suekane

Aldehyde Dehydrogenase 1 Identifies Cells with Cancer Stem Cell-Like Properties in a Human Renal Cell Carcinoma Cell Line

Cancer stem cells (CSC) or cancer stem cell-like cells (CSC-LCs) have been identified in many malignant tumors. CSCs are proposed to be related with drug resistance, tumor recurrence, and metastasis and are considered as a new target for cancer treatment; however, there are only a few reports on CSCs or CSC-LCs in renal cell carcinoma (RCC). Different approaches have been reported for CSC identification, but there are no universal markers for CSC. We used two different approaches, the traditional side population (SP) approach, and the enzymatic (aldehyde dehydrogenase 1 (ALDH1)) approach to identify CSC-LC population in two RCC cell lines, ACHN and KRC/Y. We found that ACHN and KRC/Y contain 1.4% and 1.7% SP cells, respectively. ACHN SP cells showed a higher sphere forming ability, drug resistance, and a slightly higher tumorigenic ability in NOD/SCID mice than Non-SP (NSP) cells, suggesting that cells with CSC-LC properties are included in ACHN SP cells. KRC/Y SP and NSP cells showed no difference in such properties. ALDH1 activity analysis revealed that ACHN SP cells expressed a higher level of activity than NSP cells (SP vs. NSP: 32.7% vs 14.6%). Analysis of ALDH1-positive ACHN cells revealed that they have a higher sphere forming ability, self-renewal ability, tumorigenicity and express higher mRNA levels of CSC-LC property-related genes (e.g., ABC transporter genes, self-replication genes, anti-apoptosis genes, and so forth) than ALDH1-negative cells. Drug treatment or exposure to hypoxic condition induced a 2- to 3-fold increase in number of ALDH1-positive cells. In conclusion, the results suggest that the ALDH1-positive cell population rather than SP cells show CSC-LC properties in a RCC cell line, ACHN.

Phase I trial of patient‐oriented vaccination in HLA‐A2‐positive patients with metastatic hormone‐refractory prostate cancer

To evaluate the safety and toxicity of peptide vaccination for patients with metastatic hormone‐refractory prostate cancer (HRPC) based on pre‐existing peptide‐specific cytotoxic T‐lymphocyte (CTL) precursors in the circulation, 10 patients positive for human leukocyte antigen (HLA)‐A2 with metastatic HRPC were enrolled in a phase I study. Peptide‐specific CTL‐precursors reactive to 16 kinds of vaccine candidates in the pre‐vaccination peripheral blood mononuclear cells (PBMCs) were measured, and patients were followed by vaccination with only positive peptides (up to 4 kinds of peptides). Serum prostate‐specific antigen (PSA) levels were monitored regularly. The peptide vaccination was safe and well tolerated with no major adverse effects. The most common toxicities were dermatologic reactions at the injection site. Increased CTL response to peptides was observed in 4 of 10 patients. Anti‐peptide IgG was also detected in post‐vaccination sera of 7 of 10 patients. One patient showed the disappearance of a pelvic bone metastasis after five vaccinations. Three patients showed a decrease of serum PSA level from the baseline after the vaccination, but no patients showed a serum PSA level decrease of ∼50%. The median survival duration of study patients was 22 months with follow‐up from 3 to 27 months. We consider that the increase in cellular and humoral immune responses, and decrease in PSA level in some patients justify further development of peptide vaccination for metastatic HRPC patients. (Cancer Sci 2004; 95: 77–84)

Assessment of immunological biomarkers in patients with advanced cancer treated by personalized peptide vaccination

To investigate immunological biomarkers to predict overall survival of advanced cancer patients under treatment with personalized peptide vaccination, correlations between overall survival and biomarkers, including cytotoxic T lymphocyte (CTL) and immunoglobulin G (IgG) responses to the vaccinated peptides, were investigated in 500 advanced cancer patients who received personalized peptide vaccination from October 2000 to October 2008. The best clinical response was assessed for in 436 patients, 43 patients (10%) had partial response, 144 patients (33%) had stable disease and 249 patients (57%) had progressive, with a median overall survival of 9.9 months. Both lymphocyte counts prior to the vaccination (P = 0.0095) and increased IgG response (P = 0.0116) to the vaccinated peptides, along with performance status (P < 0.0001), well correlated with overall survival. To confirm the superiority of IgG response to CTL response, the samples from advanced castration-resistant prostate cancer patients who survived more than 900 days (n=20) and those who died within 300 days (n=23) were analyzed further. As a result, both the numbers of peptides, to which increased IgG responses were observed, and the fold increases in IgG levels were significantly higher in long-term survivors (P = 0.000282 and P = 0.00045). In contrast, CTL responses were not statistically different between the two groups. Both lymphocyte numbers and IgG response were thus suggested to be biomarkers of cancer vaccine for advanced cancer patients.

A randomized clinical trial of suspension technique for improving early recovery of urinary continence after radical retropubic prostatectomy.

To evaluate, in a prospective, single‐blind, randomized trial, the safety and efficacy of a suspension technique for improving early recovery of continence after radical retropubic prostatectomy (RRP).

Phase I trial of personalized peptide vaccination for cytokine-refractory metastatic renal cell carcinoma patients

The aim of this clinical trial was to investigate the toxicity and immunological responses of personalized peptide vaccination for cytokine‐refractory metastatic renal cell carcinoma patients. Patients were confirmed to be human leukocyte antigen (HLA)‐A24 or HLA‐A2 positive and had histologically confirmed renal cell carcinoma. Ten patients were enrolled in the present study. The peptides to be administered were determined based on the presence of peptide‐specific cytotoxic T lymphocyte precursors in peripheral blood mononuclear cells (PBMC) and peptide‐specific IgG in the plasma of cancer patients. Patients received subcutaneous injections of four different peptides (3 mg/peptide) every 2 weeks. Vaccinations were well tolerated without any major adverse events. A minimal increase in peptide‐specific interferon‐γ production in postvaccination PBMC was observed, regardless of higher levels of cytotoxic T lymphocyte activity in prevaccination PBMC. In contrast, an increase in peptide‐specific IgG levels of postvaccination (sixth) plasma was observed in the majority of patients. After progression, five patients received interleukin‐2 therapy and continuous vaccination, with survival of 31, 25, 23, 17, and 15 months, but interleukin‐2 did not impede humoral responses boosted by the vaccination. These results encourage further clinical trials of personalized peptide vaccinations. (Cancer Sci 2007; 98: 1965–1968)

Combination therapy of personalized peptide vaccination and low-dose estramustine phosphate for metastatic hormone refractory prostate cancer patients: an analysis of prognostic factors in the treatment.

The aim of this study was to investigate prognostic factors of patients with metastatic hormone refractory prostate cancer (HRPC) under combined administration of personalized peptide vaccination and low-dose estramustine phosphate (EMP). From February 2001 to July 2004, 58 men with metastatic HRPC received the combination therapy of personalized peptide vaccination and low-dose EMP. Conducted immune monitorings for those patients were peptide-specific cytotoxic T lymphocyte (CTL) precursor analysis by interferon-gamma production and peptide-reactive immunoglobulin G (IgG) by an enzyme-linked immunosorbent assay. Clinical responses and survival times were also evaluated. The combination therapy was well tolerated with no major adverse effects. Increased levels of CTL precursors and IgG responses to the vaccinated peptides were observed in 29 of 37 (78%) patients and in 36 of 41 (88%) patients tested, respectively. A prostate-specific antigen decline of at least 50% occurred in 24% of patients. The median survival time was 17 months (95% confidence interval, 12-25 months). Cox proportional hazards analysis showed that a low number of lymphocytes (p = 0.0075, odds ratio 2.700), a negative immunological activity response after the vaccination (p = 0.0185, odds ratio 2.658), and poor performance status (p = 0.0347, odds ratio 2.569) were independent predictors of disease death. These encouraging results show the need for further evaluation of the combination of personalized peptide vaccination and low dose of EMP for metastatic HRPC patients.

Phase II study of personalized peptide vaccination for castration-resistant prostate cancer patients who failed in docetaxel-based chemotherapy.

Docetaxel‐based chemotherapy (DBC) showed limited clinical efficacy for castration‐resistant prostate cancer (CRPC) patients. To explore cancer vaccine as a new treatment modality, we conducted a phase II study of personalized peptide vaccine (PPV) for DBC‐resistant CRPC patients.

Early catheter removal 3 days after radical retropubic prostatectomy

Aim: We investigated the feasibility and safety of the early removal of urethral catheters 3 days after radical retropubic prostatectomy.

Localization of parathyroid glands in hemodialysis patients using Tc-99m sestamibi imaging

Tc-99m sestamibi parathyroid imaging was performed in 28 patients with chronic renal failure to localize abnormal parathyroid glands in patients receiving hemodialysis, and compared the localization with ultrasonography and magnetic resonance (MR) imaging. Methods: We imaged 28 patients with secondary hyperparathyroidism using Tc-99m sestamibi (about 600 MBq) at 10 min and 2–3 h following radiotracer injection. In addition, mediastinal images were recorded at approximately 1 h following injection to identify ectopic parathyroid glands. All patients also were evaluated with ultrasonography and MR imaging. Results: Tc-99m sestamibi scans demonstrated focal uptake in 60 glands of the 28 patients, and was categorized as slight uptake in 71.7% (43/60), and intense uptake in 28.3% (17/60). Seventeen of the 28 patients underwent parathyroidectomy. A total of 64 glands were resected. Sestamibi imaging was more sensitive for localizing abnormal parathyroid glands than ultrasonography or MR imaging. Histologic evaluation of 27 resected parathyroid glands revealed that the number of oxyphil or chief cells was not proportional to sestamibi uptake. Conclusion: Our data indicate that Tc-99m sestamibi imaging should be used initially to localize abnormal parathyroid glands in hemodialysis patients with secondary hyperparathyroidism, prior to MR imaging or ultrasonography. Sestamibi uptake in parathyroid glands may not correlate with the degree of hypercellularity of oxyphil cells.

An Open-Label, Randomized Phase II Trial of Personalized Peptide Vaccination in Patients with Bladder Cancer that Progressed after Platinum-Based Chemotherapy

Purpose: The prognosis of platinum-based chemotherapy–resistant metastatic urothelial cancer of the bladder remains poor. Personalized selection of the right peptides for each patient could be a novel approach for a cancer vaccine to boost anticancer immunity. Experimental Design: In this randomized, open-label, phase II study, patients ages ≥18 years with progressive bladder cancer after first-line platinum-based chemotherapy were randomly assigned (1:1) to receive personalized peptide vaccination (PPV) plus best supportive care (BSC) or BSC. PPV treatment used a maximum of four peptides chosen from 31 candidate peptides according to human leukocyte antigen types and peptide-reactive IgG titers, for 12 s.c. injections (8 injections, weekly; 4 injections, bi-weekly). The primary endpoint was progression-free survival (PFS). Secondary endpoints were overall survival (OS), immune response, and toxicity. Results: Eighty patients were randomly assigned to receive either PPV plus BSC (n = 39) or BSC (n = 41). No significant improvement in PFS was noted [HR, 0.7; 95% confidence interval (CI), 0.4–1.2, P = 0.17]. For the secondary endpoints, PPV plus BSC significantly prolonged OS compared with BSC (HR, 0.58; 95% CI, 0.34–0.99, P = 0.049), with median OS of 7.9 months (95% CI, 3.5–12.0) in the PPV plus BSC and 4.1 months (95% CI, 2.8–6.9) in the BSC. PPV treatment was well tolerated, without serious adverse drug reactions. Conclusions: PPV could not prolong PFS, but OS appeared to be improved with low toxicity and immune responses. Further large-scale, randomized trials are needed to confirm these results. Clin Cancer Res; 22(1); 54–60. ©2015 AACR.